Electronic multiple pole multiple throw (MPNT) switches are widely used. An MPNT switch is a switch having M poles (“P”) and N throws (“T”), where M>1 and N>1. A pole and a throw are coupled to one another by a pole-throw signal path that includes at least one switching element such as a transistor. An electrical signal is routed on a signal path between one of the M poles and one of the N throws when that pole-throw signal path is in a conductive state.
In a single transmission mode MPNT switch, only a single pole-throw signal path is conductive at one time. In a multiple transmission mode MPNT switch, more than one pole-throw signal path may be conductive at the same time. A multiple transmission mode MPNT switch may be used in a communication device that operates in multiple input multiple output (MIMO) mode. In an MPNT antenna switch operating in MIMO mode, two or more paths are conductive at the same time, thereby enabling two or more antennas to transmit or receive signals at the same time.
The poles and throws that are in conductive signal paths may have good impedance matching, resulting in minimal signal reflection and a low voltage stopping wave ratio (VSWR). The poles and throws that are in non-conductive signal paths may have unmatched impedances, resulting in high reflection and high VSWR. For some switch applications it may be useful to have good impedance matching and low reflection in most or all of the signal paths, including the signal paths that are non-conductive. A switch with these characteristics is called a non-reflective (or absorptive or terminated) switch.